<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0 ;
            padding: 0;
            list-style: none;
        }
        .uls{
            width: 300px;
            background-color: chocolate;
            color: white;
        }
        div{
            padding-left: 20px;
            height: 0;
            background-color: black;
            line-height: 26px;
            overflow: hidden;
            transition: 1s;
            
        }
        .on{
            background-color: violet;
        }
        .om{
            height: 300px;
        }
    </style>
</head>
<body>
    <ul class="uls"></ul>
    <script src="./手风琴选项卡.js"></script>
</body>
</html>